One perf test for windows VirtualQueryEx calls.

base/memory/memory_uma_perftest.cc

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <algorithm>
+
+#include "base/process/process_handle.h"
+#include "base/test/perf_time_logger.h"
+#include "base/time/time.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace base {
+
+namespace {
+
+constexpr const int kNumRuns = 1000;
+constexpr const int kMaxRegions = 1000;  // Runs of a single test seem to
+                                         // generate about 330 regions, so 1000
+                                         // should overkill.
+size_t memory_sizes[kNumRuns] = {};
+struct RunStat {
+  int num_regions;
+  TimeDelta* virtual_query_run_times;
+  TimeDelta run_time;
+} run_stats[kNumRuns];
+TimeDelta virtual_query_run_times_storage[kMaxRegions][kNumRuns];
+
+size_t GetPrivateMemoryFootprintWindows(ProcessHandle process,
+                                        const SYSTEM_INFO& system_info,
+                                        RunStat* run_stat) {
+  size_t private_memory_footprint = 0;
+  const char* current_address =
+      reinterpret_cast<const char*>(system_info.lpMinimumApplicationAddress);
+
+  TimeDelta* cur_run = &run_stat->virtual_query_run_times[0];
+  while (current_address <= system_info.lpMaximumApplicationAddress) {
+    MEMORY_BASIC_INFORMATION region;
+
+    TimeTicks start = TimeTicks::Now();
+    if (::VirtualQueryEx(process, current_address, &region, sizeof(region)) !=
+        0) {
+      ++(run_stat->num_regions);
+      if (region.Type == MEM_PRIVATE && region.State == MEM_COMMIT) {
+        private_memory_footprint += region.RegionSize;
+      }
+      current_address =
+          reinterpret_cast<const char*>(region.BaseAddress) + region.RegionSize;
+    } else {
+      // This should not happen but if it does, just go to the next page and
+      // continue.
+      DPLOG(ERROR) << "Error calling VirtualQueryEx for process: " << process
+                   << " and address: "
+                   << reinterpret_cast<intptr_t>(current_address);
+
+      // TODO(ajwong): What happens if we overflow?
+      current_address += system_info.dwPageSize;
+    }
+    *(cur_run++) = TimeTicks::Now() - start;
+  }
+  return private_memory_footprint;
+}
+
+TEST(MemoryUma, CalculatePrivateMemory) {
+  ProcessHandle current_process = GetCurrentProcessHandle();
+  SYSTEM_INFO system_info;
+  ::GetSystemInfo(&system_info);
+
+  PerfTimeLogger timer("Memory_uma_private_memory");
+  for (int i = 0; i < kNumRuns; ++i) {
+    TimeTicks start = TimeTicks::Now();
+    run_stats[i].virtual_query_run_times = virtual_query_run_times_storage[i];
+    memory_sizes[i] = GetPrivateMemoryFootprintWindows(
+        current_process, system_info, &run_stats[i]);
+    run_stats[i].run_time = TimeTicks::Now() - start;
+  }
+  timer.Done();
+
+  std::sort(memory_sizes, memory_sizes + kNumRuns);
+  LOG(ERROR) << "Memory Smallest: " << memory_sizes[0];
+  LOG(ERROR) << "Memory 95% percentile: "
+             << memory_sizes[static_cast<int>(.95 * kNumRuns)];
+  LOG(ERROR) << "Memory Largest: " << memory_sizes[kNumRuns - 1] << std::endl;
+
+  std::sort(run_stats, run_stats + kNumRuns,
+            [](const RunStat& a, const RunStat& b) {
+              return a.num_regions < b.num_regions;
+            });
+  LOG(ERROR) << "Num Regions Smallest: " << run_stats[0].num_regions;
+  LOG(ERROR) << "Num Regions 95% percentile: "
+             << run_stats[static_cast<int>(.95 * kNumRuns)].num_regions;
+  LOG(ERROR) << "Num Regions Largest: " << run_stats[kNumRuns - 1].num_regions
+             << std::endl;
+
+  std::sort(run_stats, run_stats + kNumRuns,
+            [](const RunStat& a, const RunStat& b) {
+              return a.run_time < b.run_time;
+            });
+  LOG(ERROR) << "Run Time Smallest: "
+             << run_stats[0].run_time.InMillisecondsF();
+  LOG(ERROR)
+      << "Run Time 95% percentile: "
+      << run_stats[static_cast<int>(.95 * kNumRuns)].run_time.InMillisecondsF();
+  LOG(ERROR) << "Run Time Second Largest: "
+             << run_stats[kNumRuns - 2].run_time.InMillisecondsF();
+  const RunStat& longest = run_stats[kNumRuns - 1];
+  LOG(ERROR) << "Run Time Largest: " << longest.run_time.InMillisecondsF()
+             << std::endl;
+
+  std::sort(longest.virtual_query_run_times,
+            longest.virtual_query_run_times + kMaxRegions);
+  LOG(ERROR) << "[longest] VirtualQueryEx Run Time Smallest: "
+             << longest.virtual_query_run_times[0].InMillisecondsF();
+  LOG(ERROR) << "[longest] VirtualQueryEx Run Time 50% percentile: "
+             << longest.virtual_query_run_times[static_cast<int>(.5 * kNumRuns)]
+                    .InMillisecondsF();
+  LOG(ERROR) << "[longest] VirtualQueryEx Run Time 95% percentile: "
+             << longest
+                    .virtual_query_run_times[static_cast<int>(.95 * kNumRuns)]
+                    .InMillisecondsF();
+  LOG(ERROR) << "[longest] VirtualQueryEx Run Time Second Largest: "
+             << longest.virtual_query_run_times[kNumRuns - 2].InMillisecondsF();
+  LOG(ERROR) << "[longest] VirtualQueryEx Run Time Largest: "
+             << longest.virtual_query_run_times[kNumRuns - 1].InMillisecondsF();
+}
+
+}  // namespace
+
+}  // namespace base